Simplify the following expression: $y = \dfrac{z}{4} + \dfrac{z}{2}$
Solution: In order to add expressions, they must have a common denominator. The smallest common denominator is the least common multiple of $4$ and $2$ $\lcm(4, 2) = 4$ $ y = \dfrac{1}{1} \cdot \dfrac{z}{4} + \dfrac{2}{2} \cdot \dfrac{z}{2} $ $y = \dfrac{z}{4} + \dfrac{2z}{4}$ $y = \dfrac{z +2z}{4}$ $y = \dfrac{3z}{4}$